The company had announced Gmail's offline shut-off two months ago when it said it was shifting the Web mail service's offline support from Gear, its now-obsolete plug-in, to HTML5. At the time, Google said it would drop Gear from Chrome as of version 12.

The current "stable" build of Chrome is version 11; even so, that edition doesn't run Gmail in offline mode.

"Beginning on Tuesday, May 24, 2011, users will no longer be able to use Chrome with Google Gears-based Gmail Offline," the company said in a note to users.

Until Google restores offline support to Gmail with HTML5 this summer, Google recommended that users switch to IE8 or Firefox 3.6, versions that have been supplanted by IE9 and Firefox 4, respectively.

Google plans to provide offline support to Gmail using HTML5 this summer.

"We realize that there will be a temporary gap in Gmail offline access via Chrome," said Google, "and we are working hard to deliver offline capabilities through a new Gmail Offline Chrome Web app as quickly as possible."

Firefox 3.6 can still access Gmail in offline mode, but Google's own Chrome cannot.